java - 如何使用 JDBC 从 mySQL 获取特定列？

Question

    PreparedStatement ps2;
    ResultSet rs2;

    String username = jTextField_username.getText();
    String userpassword = jTextField_userpassword.getText();

    String sql = "SELECT distinct kalanizin from users where username =?";
    String[] resultsetarray = null;

    try {

       ps2 = MyConnection.getConnection().prepareStatement(sql);
       ps2.setString(1, username);

       rs2 = ps2.executeQuery();
       String result = rs2.getString(0); // i want this String to hold the first result

大家好。我有一个问题一直困扰着我。正如标题中所说，通过使用 JDBC，我想从我的数据库中获取一列。例如

Select * from users where username = "blabla"

我希望 Java 执行此查询并获取它找到的第一行。然后放入字符串或整数。正如您在顶部看到我糟糕的代码一样，它无法做到这一点。我试图通过使用语句来完成此操作，但它仍然不起作用。谁能帮我？那将不胜感激。附言。抱歉我糟糕的变量名和使用我的本地语言作为变量

Answer 1

如果你知道列名你可以使用像getString(columnLabel)这样的方法而不是 getString(columnIndex):

Retrieves the value of the designated column in the current row of this ResultSet object as a String in the Java programming language.

columnLabel - the label for the column specified with the SQL AS clause. If the SQL AS clause was not specified, then the label is the name of the column